Pressure-indicator.



H. P. 'KRAFT & M. C. SCHWEINERT.

PRESSURE. INDICATOR. APPLICATION FILED JULY 14. 1909.

Patented Mar. 28, 1916.

3 SHEETS-SHEET I.

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PRESSURE INDICATOR.

APPLICATION FILED JULY I4. 1909- Patented Mar. 28 1916.

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INVENTORSZ WITNESSES:

H. P. KRAFT & MIC SCHWIEINVERT.

PRESSURE INDICATOR. APPLICATION ms!) JULY (4. 1909.

Patented Man- 28, 1916.

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WITN Qw UNITED STATES PATENT OFFICE.

HENRY P. KRAFT, OF NEW YORK, N. Y., AND MAXIMILIAN CHARLES SGHWEINERT, OF WEST HOBOKEN, NEW JERSEY.

PRESSURE-INDICATOR.

Application filed July 14, 1909.

and State of New Jersey, both citizens of the United States, have invented certain new and useful Improvements in Pressure-Indicators, of which the following is a specification.

This invention relates to pressure indicators, and is especially adapted for indicating the pressures in pneumatic tires or other similar devices.

'. .According to our invention we provide a pressure indicator which in its preferred form is adapted to be applied directly to a pneumatic tire valve of any standard construction, or to an intermediate pump connection which itself is applied to a valve, so

that the pressures within the the are indi cated during the act of inflation.

In the most complete form of the invention, means are provided not only for indicating the pressures within the tire,-but also for relieving the pressure when the latter rises to a predetermined height, so that it is impossible to pump into the tire'any greater 3O attachment to a pump and a tire valve; Fig.

2 is a diametral section of the device of 1 on a larger scale; Fig. 3 is a .view showing various parts of Fig. 1 in elevation; Fig. 4 is a view of another form of the invention adapted to act as a pressure findicator only, and also adapted to be inserted directly in the top of a tire valve to determine the pressure therein without the intervention of a pump coupling; Fig. 5 is a diametral section'of Fig. at on a larger scale; Fig. (1' is an elevation of the several parts of the indicator detached; Fig. Tis a view of another modification in which the deflating .or relief mechanism is omitted; Fig. 8 is a diametral section of Fig. 7 on a larger scale;

Specification of Letters Patent.

Patented Mar. 28, 1916.

Serial No. 507,565. 4

Fig. 9 is a view of a modified form of indicating hand or pointer; Fig. 10 is a plan of Fig. 9; Fig. 11 is still another modification; and Fig. 12 is a plan of Fig. 11.

Referring first to Figs. 1 to 3 of the drawings let' A indicate a suitable casinghaving swiveled to its upper end an extension B, such extension having a flange C adapted to it over a flange D formed on the casing A.

The flange C is preferably provided with a -knurled portion E by means of which the extension B may be easily rotated for a purpose hereinafter described. At its lower end the casing A is formed with a flange F de; signed to be engaged by a coupling G, so that the casing may be secured to a pump connection H or other member.

lVithin the lower part of the casing A is located an expansible tube I preferably formed of rubber, the lower end of which is provided with a flange J by which it may be fastened at the lower part of the casing, preferably by being squeezed against the pump connection H or other device by the coupling G, so that a tight connection is made at this point. The tube I which is in the form of a thimble, that is to say, is closed or partly closed at one end, forms on its interior an expansion chamber K within which the air, which is to be measured as to its pressure, is admitted in any suitable way. The upper end of the thimble I in these figures is partly closed, it being perforated only sufliciently to permit the passage of a screw L, by-which the thimble is connected .to an indicating member M,- the screw having a passage N in the construction shown by which air is admitted to a valve chamber 0 formed in the indicating member M. Mounted in the valve chamber O is a valve seat P held in place by a screw plug Q, and co-acting with such seat is a valve proper R connected with a stem S. These parts are preferably of the usual Schrader valve typ although there may be many suitable constructions. I

hen there ,is air under pressure inthe chamber K'this is communicated through the bore or opening N in the screw L, and thence to the valve chamber 0, forcing the valve proper R to its seat. Under these conditions the pressure within the chamber 'K will extend the tube or thimble 1 and raise the indicating member M to a greater or less extent depending upon the de f B may be formed of pressure. Any Suitable means for indicating the movements of the member Mfinay be adopted. We prefer, the extension B -Wltl1' a through which may be edge U of the member slot or opening T or other indicating marks-as illustratedin Fig. 1.

While the resistance 8f the thimble or tube I may in some cases be utilizedfor 0p.- posing the pressure, we prefer to augment this by a spring V, the lower end of which is expended as shown to engage the lower end of the casing A while the upper end is contracted to engage a reduced the indicating member M. y this means the spring constitutes a load which increases With the pressure. The spring also performs'an'important function in connection with the'tube IA If ted, there would be-liability of the tube expandinglaterally under the pressure so that it would rub against the inner sides of the were only as long as the I this means the spring is adequately material extent force its way between in: member M casing, and be liable to other deformations. The tube prevents this expansion and constit'utes a protecting expansible and contractible casing or shell for the tube. An important feature in this connection is the proportioni'ng ofthe spring If this spring tube, the convolutions of the spring would separate to such an extent during the maximum expansion of the tube as to minimize the protecting effect of the spring. Ve hence make the effective length of the spring considerably longer than the tube, as shown in Fig. 2 wherein the spring is effective from its point of connection with the reduced part'of the indicatto its point of connection with the flange F of the casing A. By places a suflicicut load upon the movements of the indicating member M to secure a proper indication of the pressures, while at the same time the convolutions of the spring separate-ho so small an extent in use that the tube" or thimble protected, and does not to any such ccnvoluti-ons;

According to our invention we prefer to provide means whereby when a predeterthe extension B is portioniw; which mined 'o r set-pressure is reached no further substantialincrease of pressure within the tire is permitted. The mechanism provided for that purpose in the present construe-5 tion is shownbest in Fig. 2. In this figure provided with a reduced 1s screw-threaded on its interioryand a plunger or gage X is screwed in saidvextension, a lock nut Y being p'ret erably rovided-tpfyhold the P it OnS. To set t e device thi? locknut Y. is l'oo'ened, and the plunginscrewed in until its lower end opposite however, to provide observed the top The extension 1' suitable .graduations I portionQof" air.

the spring. were omit but a lateral opening the tire and the chamber K lunger in indicating member M rises under the pressure, the stem S of the valve R the lower end of the plungeriX, and further movement pushes. the valve engages a slight R from its seat, permitting the escape airfroni the valve chamber 0 ber K. Under these conditions when our device is combined with a pump connection, theincomingair from the pump instead of flowing to the tire bers K and 0 into the extension B and thence through .the opening T to the outer connection A a nipple member C adapted to be connected with the rubber pump tube D. The extension A has a bore E leading to the vertical bore F of the connection; which latter is extended, downwardly into a projection G designed to enter the top-of a tire valveshell H'.- The projection G is preferably imperforate on its lower side I is provided through and expansion champasses through the chamfave illustrated .theinvenwith the pump connection 1 nnection consists ofa' plug while there is screwed to the end of the which the air passes into the tire valve. I The function-of the impert'orate lower wall is to press down the stem J of the tire valve, so that during the the tire valve is held in itsgppen position.

' The purpose of this construction is to pro vide a free connection for the air between F. In use witha pump the lateral extension A valve to prevent the back flow of air into the pump. The lower end of the extension H is preferably provided with a coupling K swiveled thereto, and adapted to screw on the end of the tire val e shell avhile a packing L is fitted around the projection Gfto make a tight joint. with the valve shell. In order to avoid jumping or pulsating of the part M, we preferably introduce into the valve B of serves as a check the pump connection or othersuitable point a plug M which has a T-shaped bore N leading at right angles into the central bore F of the part H. By this construction the direct passage of air into the expansion chamber'K isavoided it being necessary for the air to. work itself around into the angular passage N; when the air is being pumped into-the device therefore its put sating effect is broken up before it reaches the expansion chamber K.

In Figs. 4 to (i we have shown a form of the device in which the deflating.mechanism is omitted. In this form of the device the shell A is provided with an extension l3,

punipihg operation through the .bore

and the indicating member M is constructed end. The tube forms an expansion chainber K into which air from thetire or other device passes. In these figures we have also shown the device as applicable for use as an indicator without the pump connection. In this construction a plug H .is provided to which the shell A" is united by a coupling G The plug H. is provided at its lower end with a nipple G and a passage F leading through the plug and nipple. A pin G extending across the nipple is providedfor pressing down the deflating pin of the valve when the device is applied. As in Fig. 2 a spring V surrounds the tube to protect it, and to place a proper load upon the indicating member. In the use of this embodiment of the device it is necessary only to press the nipple G into the end of a valve shell until a tight joint is made by the packing washer L". whereupon the deflating pin of the tire will be pressed inward, and the air from the tire will flowback through. the valveinto the expansion chamber K,

In both of the constructions j ust' described it is preferable to swivel the extension B i to the casing A in order that the opening T (or T maybe turned opposite the user no matter what theposition of the. indicator may be. i

In Figs. 7 and 8 we have illustrated an otherembodimentof the invention wherein tit is applied to "a connection especially adapted for tanks or flasks as distinguished- "from pumps. For this purpose it is not necessary to provide a checkvalve inthe lateral extension A -of the connection H Theextension A". may be coupled up with the flask or tank of'compressed air in any suitable way. In this construction we have shown the casing A as formed in one piece with a slot T at its top. The indicating member or plunger M moves upwardly and downwardly in the casing as before. The spring V is connected to the plunger 'near its top as shown, and to the casing at its bottom as illustrated in Figs. 2 and 5.

In either of the devices herein described the indicating means may-be brought to the exteriorofthe casing or extension, if desired.

In Figs. 9=to 12 we have shown such a device which consists of, a metal pointer Z fixed to'the top of the plunger M Preferably the upper end of the casing or extension is flattened as shown at Z (Figs. .11

' and112) in which case the pointerZ will be flat as illustrated.

In any of the forms shown it is important that the extensible tube be constructed as a thimble, that is to say, with one end at least partially closed. ln the construction of l i l to ri lt much .i'acilitates connection with the plunger, and permits a leak-tight joint to be easily formed. In Figs. 4 to 8 this construction provides an absolutely secure and leak-tight packing for the plunger, so that escape of airis impossible, while also permitting the plunger-and tube to be'unconnected with each other, thus greatly simplifying the assembling and disassembling of the parts. tant that the tube be. formed with a flange at its lower end as this much facilitates its connectionwith the casing or other part to which it is attached, and provides an easily made leak-tight joint at this point.

"While we have shown and described certain embodiments of the invention, it is to b understood that we do not wish to be since various changes may be made therein without departing from the invention.

We do not herein claim specifically the forms illustrated in F igsal to 3 and 7 to 12, as these form the subject-matter of a divisional application filed by us February 23, 1916, Serial No. 79,880.

\Vhat we claim is 1. A pressure gage comprising a tubular casing, a plunger head movable in the direction of length ofsaid casing, said casing acting as a guide for said plunger head, means sliding along'said casing for indicating the movements of said plunger head. an extension spring connected at its upper end to said plunger head and connected atits lower end to said tubular casing, and an elastic imperforate thimble fitting within 'said spring. the upper end of said thimble engaging the under/ side of said plunger head, and means for connecting the lower end of said thimble with a leak-tight joint 2. A pressure gage comprising a tubular easing, a plunger head movable in the di-' rection of length of said casing, said casing having a tubular member for guiding said plunger head, an extension spring connected at its upper end to said plunge-r head and connected at its lower end to said tubular casing, and an elastic imperforate thimble fitting within said spring. the upper endo said thiinble engaging the under side of said plunger head, and means for connecting the lower end'of said thimble with a leak-tight joint to said casing, means at the lower end of said casing for connecting said gage to a tire-valve casing, and means at such lower end for unseating such checkvalve.

3. A pressure gage comprising a tubular casing, a plunger head movable in the di- It is also impor rection of length of said casing, said casing having a tubular member adapted to extend beyond said casing but held against lateral movement with relation to said casing, said tubular member acting as a guide for said plunger head,'an extension spring connected at its upper end to said plunger head and connected at its lower end to said tubular casing, and an elastic unseating such check-valve.

4:. A pressure gage comprising a tubular.

casing, a plunger head movable in the'direction of length of said casing, said casing having a swiveled longitudinally slotted extension in which said plunger head is movable, an extension spring connected at its upper endto said; plunger head and con-V nected at its lower' endto said tubular casing, and an elastic imperforate thimble fit- :zting within said spring, the upper endof i thimble engaging the under side of said plunger head, and means for connecting the lower end of said thimble with a leak-tight joint 'to'said casing, means at the lower end of said casing for connecting said gage to a tire-valve casing, and means at .such lower end'fonunseatin'g such "check-- valve. v

5. A pressure gage comprising a casing,

'a;..plunger-head, an extension spring, an

elastic imperforate thimble fitting within saidspring, means for connecting said spring and thimble to said casing, means for connecting said gage to a t1re-valve cas- 1 ing. and meansfor unseating a check-valve.

saidcasing comprising a straight tubular portion n which said plunger-head is'longitud nally movable and guided, and of a -for connecting said gage to a tire valve casing, and meansfor unseating a check- .valve, said casing comprising a straight tubular portion in whichsaid plunger-head is longitudinally movable and guided, and

of a length to contain said'plunger when in extended position, said plunger head indioating degrees of pressure by its position in said tube, said tubular portion having a slot therein through which the positions of said plunger-head are observable.

7. A pressure gage comprising a casing, a plunger-head, an extension spring, an elastic imperforate thimble fitting within said spring, means for connecting said gage; to atlre-valve casing, and means for unseating a check valve, said casing comp rising a straight tubular portion, a base piece.

and. a 'e'oupling adapted to connect said tubular portion and base piece, said spring and fthimble being clamped at one end be: tween 'said tubularv portion and base piece,

being longitudinally movable and guided n saidtubular portion, said tubular member. being of a length to contain said plunger-head when in extended position. said plunger-head indicating degrees ofpressure by .its position in said tube. In witness whereof, we have hereunto signed our names in the presence of two subscribing Witnesses.

HENRY P. KRAFT.

MAXIMlLlAN CHARLES SCHWEINERT.

Witnesses:

THOMAS F. WALLACE, FRED Wnrm. 

